Slab door



June 24, 1958 P. l.. SANDERS ET Al. ,2,839,792

. v SLAB DooR Filed sept. 13. 1954 2 sheets-sheet 1 PUPRT 6. HALEY v INVENTORS Bvogmfoga.

June 24, 1958 P. L 'sANDERs ETAL 2,839,792

SLAB DOOR Filed Sept. l5. 1954 2 Sheets-Shea?I 2 H6. l c-. 6

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FRANC/5 E. HALEY PUPEET G. HALEY INVENTORS P41/L L.. SHA/pees.

United States Parmi" om@ 2,839,792 'Patented June 24,1958

SLAB Doon Pzaul InSanders, Francis E. Haley, and Rupert G. Haley, 'i

Santa Monica, Calif. n y Application september 13,1954, seal No.'v 455,484 3 Claims. (ci. zii-fas).

"Thisvinvention relates to the construction of doors of the type generally known as slab door,. wherein an open',

frame structure is faced on respective sides by f acingsl of y sheet material such as Masonite or thin plywoodfthe marginal faces of the frame constituting the main area of the marginal faces of the door. Such a door'gives the general appearance of a solid slab with plain at faces,

v although actually its interior is-lar'gely hollow, whereby the door is of relatively lightweight construction though exceedingly sturdy. f v f ,f

The facings of the door are adhesively attached to the faces of the frame by a suitable vglue or cement. -When the facings are 'thus bonded Ito the frame, they .pennanent1y..secure the various componentsof the frameto-l gether inthe selected door form. Iny the process of fabri. cating the door, howeverthe. frame components,` after being assembled, must be temporarily', attached together i'nzfthproper positions, so vthat theframe structure may lretain its yshape .until-.the-facings have been bonded thereto.. A numberof expedients for thus temporarily attaching the frame components togetherhave been utilized, a common one being that of drivingstaples into adjoining frame components across a joint line. gatedfasteners also can be used. However, in allcases where metal fasteners are used, there is created ahazard for the cutting tools of the carpenter or cabinet.- maker who subsequently tits and hangs the. doors .andi ontsmecesses ltherein for the reception of hardware such as locks,

latchesy and hinges. This is a very serious. objection-to.

' all slab' doors having metal fasteners inthe jointsbetween sections of a frame, Ycompletely covered and hidden-"by the wood Veneer or Masonite facings of the door.- Accordingly, a primary object of the invention isto provide a slab door which contains no metal fasteners of any kind and is therefore completely free of this objection.

Where metal fasteners are driven into the vjoints of a slab door frame, in order that the facings maythereafter lie atly against the faces of the componentsin the areas:

in thefareas where it is thus held away from the surface ofthe frame. Y

.One of ithe objects of this invention isto provide a slab door' ,const ructionwhich is devoidv ofstaplesfor other. metaljfastener, elements and which provides in-all cases afsmoothhat intimate face to face contactbetwe'en" thel facings andthe frame surfaces throughout the entire-areas of the frame. t Y A further object is1to provide animproved method of fabricating such a slabdoorn v 1.

yIn thernilling of components for frame structures such as that of a wooden door, using, as the basic construction, the common tongue and groove structure wherein a tongue,'mil1ed on theend of one component, isr inserted into a groove milled in an adjoining component, the slight deviations from atness, i. e. warpage or twisted conditions which is constantly encountered in components fabricated from wood, together with the fairly loose toleraneeswhich are inherent inwoodworking machinery, inevitably results in-slight dimensional variations in the grooves and tongue structures (e. g. the thickness of the tongue, the width Vof the shoulders on either side o f a tongue, the width of the groove or the Widthof the thick-' ness of the cheeks which define a groove); Occasionally,

these departures from the intended dimensions become suiiiciently great so that the partl is discarded as waste. Careful manufacturing practices makeit possible to red uce the inaccuracies to a tolerable minimum, and yet even in the case of many parts which are actually used, the dimensional deviations are such as to preclude the attainment of a flush relation between adjoining areas of the frame component surfaces, and there will occur slight oisets in the frame where the facing does not lie smoothly and flatly against these adjoining areas vofthe frame surface. Even under the relatively high pressures' that are applied in the gluing press, it is impossible'toy suliicientlyfcompress the projecting areas .so.,as' to force the parts into" a flush relation, and noticeable high spots will occur in the surface of the spacing over such irregular areas. i Y

l A further object lof this inventionis to provide a slab door 'construction which is such as 'toautomatically pro-,

vide a self aligning action between adjoining frame components inthe surface areas thereof, when subjected to the pressure of an assembling press. Conson'ant with this object, a further object is to provide an improved method of fabricating a slab door so as to attain this self aligning action in the press.

Other objects will become apparent inthe ensuingL specitications and appended drawings in which:y

Eig. 1 is a perspective view of a slab door embodying our invention, with a portion of the facing thereof'broken away to illustrate the internal structure; Fig. 2 is a fragmentary detail sectional perspective view of the frame structure, taken as indicated by the `line 2- 2 of Fig.-l;

Fig. 3. is a detail sectional view taken on the line of Fig. 1;

Fig.. 4 is a detail sectional View taken on the line 4-4 of Fig. l;-

,Fig. 5 is a schematic view illustrating an initial stage.y of the process of assembling aslab door yin accordance with the invention; v

Fig- 6 is a schematic View showing another stage in theassembly; y.

Fig. 7 is a schematic View showingV a later step in the,

assembly operation. .v

Fig.. 8 isa schematic view illustrating a dimensional,i

deviation occuringinadjoining parts of a slabdoor in the processof fabrication according to the invention; and.4 Fig.V y9- is a schematic view showing how the invention f adapts-theV door to suchdeviation.

Referring now in detail to sheet l of the drawings, and f to Figs. 1-4 inclusive shown thereon, we have shown in these-figures, as an example'of one form in which the invention mayl beembodied, aslab door which comprises a frame structure indicated-generally by the'referencecharater'*AV and facings indicated generally by the reference character-1B. In accordancev with conventional practice,l

the facings B may be of a hard, bonded and calendered fiber sheet such as that commonly known by the trade name Masonite; whereas the frame A may be of soft wood, with the facings B bonded or cemented thereto by a suitable cement or glue. f 'Y Referring now to the frame structure A in detail, it comprises four peripheral frame 4bars includingthe pairA of opposed parallel upright bars 11 and 11' and a pair of opposed parallel horizontal members, i. e. the top and bottom frame members 12 and 12'. T he members of one pair of such peripheral frame members is provided with a groove; the members of the other pair of spaced parallel members are provided with tongue means for insertion into such grooves. In the particular example shown, the grooves are the longitudinal grooves 13 in upright frame members 11 and 11'; and the Vtongues are a pair of laterallyspaced tongues 14 provided at each end of each of the horizontal bars 12, 12'.

The tongues 14 when received in grooves I3 are adapted to maintain yielding spreading pressure against the side walls 15 of the 4groove 13. Accordingly', the tongues 1'4 are initially fabricated with their outer side walls 16 spaced somewhat farther apart than the side walls 15 of the groove 13, whereby the tonguesyare received in the groove 13 with an interference t, 'and must be sprung toward one another in order to be so received. In the drawings, the dimensional difference between the original spacing of tongue walls 16 and that of groove walls 15V is shown in exaggerated contrast, forfthe purpose of making said dimensional dilerence readily apparentv from an inspection of the drawings. u mensional difference is considerably less and the tongues 14'do not attain the degree of convergence which is shown for example in Fig. 3. will, when received in the. groove 13, be .flexed toward one another, the portions thereof between their roots and their areas of engagement with walls 15 beingcurved, and the outward pressure against walls 15 being largely concentrated at the areas adjacent the outer corners thereof, where some compression will take place between thesaid outer corners and the tongue side wallsV 16'.l Thus theV tongues will be frictionally locked or -latched to the upright members 11, 11, whereby'the frame structure is held in assembly temporarily during the stepsof'handling the frame, applying the facingsB thereto and assembling the doors in suitable clamp means for applying pressure that is utilized in effecting a close bond between the facings and the faces of the frame.

TheY tongues 14 are separated` by a s-lot 17 which is at al1 times unobstructed, the groove 13 being a plain' rectangular groove and the tips ofthey tongues being free to flex toward one anotherV during the various stages of fabrication of the door, whereby to provide a `resilent joint between the adjoining frame bars. To be more specic, the` joints between the bars, provided by tongues 14, is of a resiliency such as to provide for yield between the adjoining frame members in a direction transverse to' the general plane of the door. Thisv yielding quality is made use of in a self aligning operation which characterizes the' assembling method described hereinafter. In addition, it reduces to a substantially constant minimum the loads which may be set up between thefacings and the frame members when a facing is bonded, under clamping pressure, 'to adjoining frame surfaces which initially areY not ush. Thus, in the fabricated door, the tendency of the facing to pull away from one of'the frame surfaces In actual practice, the di-v As indicated in Fig. 3, the tongues' under the diierential loads established-in this manner, is

18;.` each. terminatingat' itsV outerv end inanf abutrnentfv shoulder 19-and'each -spaced fromflafrespective tongue 1liAVV by, a lateral .slot "20;: Shoulders` 119'iaree offset rearwardly from the tips of tongues 14 the depth of groove 13, whereby the shoulders 19 may engage the inner lateral margins of frame bars 11, 11 on respective sides of grooves 13, to provide the spacing between vertical bars 11, 11', with the tips of tongues 14 clearing the bottoms ofv grooves 13 as indicated in Fig. 3. The lateral slots 20 are-,of sufficient depth to provide Vin the abutment wingsu 18 adequate lengths to embody a lateral resiliency which is 'util-ized in compensating for thickness variations between adjoining frame members, in a manner 'wliiclrwill be more ffully pointed out in the ensuing description of the fabrication method. Furthermore, this resiliencyf the abutment wings 18 is such as' to reduce to a tolerable minimum` the residual loads set up between a facing and one of two adjoining frame members of initially greater thickness than the other, in being placed under compression in the bonding operation. This eliminates the tendency for the facing to be forced awayy from the thinner frame lmember as the result of such residual loading. i v

In addition to the peripheral frame bars described above,A

the frame includes a series of intermediate stringers 21 and 21' and a pair of lock-casing slabs 22. Each of the 'stringers 21 and 21' has at' each end thereof, tongues 14,

grooves 13 and on the' other side with longitudinally ex-V tending' flanges 14 (Fig. 4`) spaced by 'central slots 17", together with abutment wings 18" spaced from inneri anges514 by lateral grooves Z0, each of these parts" and grooves having the same cross sectionaldimension's as theA parts and grooves 14, 17, 18 and 20 of the endsof horizontalfbars 12, '12'. grooves 13 in'thesam'e manner as tongues 14', and the' abutment wings 18" abut against frame members 1'1, '11'y inthe same manner las shoulder members V18.

Tongues 14' of stringers 21' are received ing'ro'ov'es' of lock'casing slabs 22, inthe same manner as tongues 14' of frame ba'rs'12 and 12'.

` In each-case, the tongues 14, 14', 14" andthe shoulder members 18, 18', 18" extend the full vertical dimension' of the respective parts 12, 21 and 22 (the width of bars 12` and 21 andthe length of slabs22).

The lock .casi-ng slabs-22 provide,'intermediatetlie bot' tornrand'top' of the door, added' width to the vertical frame members 151,'11", such that there is plenty of area forv the lock cavities which are conventionallyy provided' in' `door structures.

thecutting operations in which the lock cavities are formed'.` Stringers 21 and 21' are evenlyspaced Vfi'orn'top to bottom of the' door, for a maximum' distribution of" support to the facings.

Facings B' are attached to the `forward and rearfz'a'c'es respectively of frame membersll; 11, 12, 12', 21, 21'

and 22 by lms-fofwaterproof glue or cement, to' prcnvidel the. sole means for permanent fastening of the parts* togetherin'lthe' form of a slab door. Thel tongues`1'4`,

14, 14" provide lateral support resisting any loads-'that might-be applied toY the doorf in shear between the: adjoining surfaces of frame members such asy members 11, 12, etcl, tending tot shift these members into" offset i relation'l in the direction transversely of the general4 plane kof `the door. This resistance to such otfsetshifting is aY yieldingrone, but adequate to support the'relatively'` thin facings Br against th'etendency toA be1 rupturd in' shear as the result of any such loads.

' Themethod of'fabricatng the slabdoo;

Referring now to Figs. 5 to"9A inclusive;` oni'slieetl I a distance slightly less than.

j cutters in an end milling operation.

of thekdrawings, and with specific reference first to Fig. 5, there isshown in that figure the step of initially assembling a pair of adjoining frame sections such as the vertical peripheral frame bar 11 andthe upper horizontal bar 12. The grooves 13 of upright bar 11 are-formed by a conventional rabbeting operation and the tongues 14, abutment wings 18 and slots 17 and 20 are, in the initial milling operation, fabricated by a suitable 'gang of dado The same gang of cuttersis employed 4for milling the parts 14', 18' etc., of the stringers 21 and 21',- and for rabbeting the flanges 14", 18" and grooves 17 and 20" of lock casing slabs 22. Subsequently the outer tip corners of tongues 14, 14' and anges 14" respectively are mitered at 23 so as to facilitate entry of the tongues and flanges into the grooves 13, 13 etc.

n The parts having been Afabricated in the manner indicated above, a set of parts shown inrFig. 1A are arranged on a suitable supporting surface, preferably horizontal, with the transverse members 12, 21, 21 and 12' being arrangedrin properly spaced relation and the vertical members 11, 11' and 22 being then brought into place from respective sides until the various tongues, anges and groovesl are in the entry relation shown inFig. 5. If desired, the lock casing slab 22 may be attached to stringers 21' to provide preassembled central units which may then be arranged as units between the stringers 21 and vertical bars 11,'11 prior to .bringing the bars 11, 11 together. l y v A satisfactory and desirable method of quickly determining the relative positions of the various parts of the door Vframe is to utilize an assembly jig havingfvarious` projecting parts corresponding to the spaces between the door frame parts, the latter being simplyftted against the projecting parts of the jig. After the frame is assembled it can be lifted away from the jig.

With the parts properly positioned as indicated above, the side frame bars 11, 11 are pushed toward one another, forcing the tongues ,14, 14' and flanges 14 to enter the Vgrooves 13 of the bars 11, 11', until the various abutment wings 18, 18', 18" are in snug bearing engagement with the respective frame bars 11, 11'.

With the frame thus fully assembled, the yielding outward pressure of tongues 14, 14 and llanges 14" against the walls of grooves 13 is adequate to hold the Vframe in assembled relation while it is handled (e. g. is lifted away from the assembly slab and placed on top of a facing B lying upon a suitable horizontal support).

Before applying the frame to the f acings, the respective forward and rear faces of the frame members are coated with a suitable bonding adhesive. To this end, the frame is passed over or between the adhesive applying rollers of a suitable adhesive applying'apparatus so that both faces of the frameY are coated at substantially the same time. The lframeis then laid upon one of the facingsy `as previously indicated. y

Apreferable method ofY applying theframes to the casing is to build up a stack of alternating facings and frames as indicated in Fig. 7. The facings for the lowermost door of the stack may be made for example upon a horizontal supporting surface 25. The first frame after being duly coated with adhesive is then laid carefully upon the first facing in a manner to bring the edges of the frame and the edges of the facing into satisfactory registry.

Another facing is then laid over the frame and the edges are properly tted to the margins of the frame. The lower facing for the next door is then laid on top of the door which has just been assembled, and another door frame, after being coated, is laid in the stack. Thus the stack is built up to a pre-determined height. The completed stack of assembled doors is indicated at C in Fig. 7. A pressure applying platen 26 is then brought to bear against the uppermost door of the stack, and downward pressure is applied as indicated by Vso arrow 27. A suitable press, adequate for applying fairly high pressure to the stack of doors, is employed.

The stack of doors is left in the press an adequate time to provide for thorough settingor curing of the bonding agent. Finally, the doors are removed from the press and are then in completed form, ready for finish trimming and sanding operations which may be applied to complete the doors ready for painting.

While it is preferable in quantity production of slab doors to arrange them in stacks for the application of pressure, itis to be understood that the invention is not restricted to the stack type of operation. As an alternative, the invention contemplates the pressing of a single door at a time in a heated platen press wherein each individual door is inserted in a respective opening between separating platens; or it would be entirely possible to utilize the invention in a single simple clamp or press having a capacity for receiving only one door at a time.

During the assembling operations, the invention provides for an automatic self aligning action for the following occasional occurrences:

y(a) Misplacement of groove or tongue laterally from its proper position. Through the tolerances existent in milling machinery, the fabricator of tongue and groove mill work is constantly faced with appreciable variations in the location of grooves and tongues with reference to the thickness of the milled parts. Such variations are commonly caused by warped conditions in the milled parts, and cannot be completely avoided. Where the warpage istoo severe the parts may have to be discarded. However, it is highly desirable that the majority of milled parts which are thus produced with dimensional deviations from the designed dimensions, be rendered usable. The present invention provides for this in the following respects: by `reference to Fig. 8 it will be assumed that the thickness of the respective parts 11 and 12 is reasonably equal so-that the tongues 14 are displaced upwardly, as viewed inl Fig. 8, with reference` to their designed positions. It may also be assumed, in this example, that the uppermost slot 20 is wider than it should be and that the lowermost slot 20 is narrower than it should be. In this assumed example, the dotted line 28 will be taken as the'outer face of the lower side of bar 12V and lowermost wing 18. It Awill now be apparent. that, as initially assembled, frame parts. 11 and 12 will be slightly misaligned in that upper abutment wing 18 will project slightly above the adjoining surface of vertical bar 11 whereas lower abutment wing 18 will be recessed slightly upwardly from the lower surface of bar 11'- as indicated by dotted line 28.

VThis condition will remain during the assembling of the frame between the facings B, but when pressure is applied to the doors in the stack C, it will force frame bar 12 downwardly with respect to bar 11 as indicated by arrow 29, the tongues 14 yielding in order to allow this self-aligning action wherein the faces of bar 12 become flush with the faces of bar 11. v Y Another vcondition which frequently occurs is a dimensional variation in thickness between adjoining frame bars. This is illustrated in the full line showing of Fig. 8, bar 12 being shown las being somewhat thicker than frame bar 11. In this case, a conforming action is provided for by the yielding quality of the upper abutment wing 18, the downward pressure against the same causing it to ex downwardly as indicated by arrow 31 in Fig. 8 until it assumes the position shown in Fig. 9. Correspondingly, the upper facing B will bend slightly in the area indicated at 32, to cause the facing to lie flatly against the adjacent faces of both frame members 11 and 12 and to conform to the revised contour of the upper wing 18. e

In this shifting movement of tongues 14, the exure of the lower tongue will be increased and that of the upper tongue will be relieved, the tips of the tongues shifting slightly upwardly as indicated by arrows 3 0, while the roots of the tongues move slightly downwardly with the bodily downward shift 'of frame bar 12. During this conforming operationfit is. not necessary for thetongues 14v to shift position, tlie lower wing'lS being initially flush with the lower side of bar 11 in this second assumed example.

While the foregoing description relates specifically to the manufacture of slab doors,V it is to be understood that the invention can be extended to the manufacture of other hollow articles such as table tops, wall panels, or sections, and partitions for pre-fabricated ybuilding structures, or any other type of panel structure or hollow wall structure, where higlrprecision finish is required.

We claim:

l. A joint for a slab door core, comprising: a frame bar having a longitudinal groove defined between spaced flanges having substantially parallel, opposed inner walls and having marginal walls disposed in a common plane normal to said inner walls; and a joining bar having at its end a central slot, tenon tongues on respective sides of said slot, projecting into said groove, and a pair `of resilient abutment wings on respective sides of said tongues, in opposed embracing relation to the roots of the respective tongues, said wings at their tips having squared abutment shoulders set back from the tips of said tongues and in closed-joint abutting engagement with the said marginal walls of the respective flanges of said frame bar; said joining bar having lateral slots between said tongues and the inner faces of said wings whereby said inner faces are spaced outwardly from the outer faces of said tongues and from the planes of said inner walls of the groove, said outer tongue faces being substantially parallel, and said tongues being sprung toward one another by the embracing action of said flanges so as to exert yielding outward pressure against said inner walls of the groove such that said tongues are frictionally gripped by said flanges to secure said joint in assembled condition without the aid of fastening elements; said abutment shoulders of said wings being in freely shiftable association with said marginal faces of the frame'bar against which they are abutted, whereby said wings are freely yieldable inwardly against the pressure of facing sheets covering the outer faces of said bars, whereby to achieve a flush relation between the respective outer faces of said wings and said flanges.

2. In a slab door: a frame bar having a longitudinal groove dened between spaced flanges having substantially parallel opposed inner walls; a joining bar having at its end a central slot, tenon tongues on respective sides of said slot, projecting into said groove, and a pair of resilient abutment wings on respective sides lof said tongues, in opposed, embracing relation to the roots of the respective tongues, said joining bar having lateral slots between said tongues and the inner faces of said wings whereby said inner faces are spaced outwardly from the outer faces of said tongues for yielding movernent toward the same, said wings having at their tips abutment shoulders in abutting engagement with the marginal faces of the respective flanges of said frame bar; said tongues exerting yielding outward pressure against Asaid inner wallsY of said groove whereby said tongues are frictionally gripped by said flanges; and facing sheets, attached to the outer faces'of said bar and bridging across Vthe joints between said abutment wings and said flanges; said abutment shoulders and marginal flange faces being in closed-joint contact with one another inv a `plane substantially at right angles to said tongues and wings, and being freely shiftable in said plane relative to one another so as to accommodate inward yielding of said wings to achieve flush relation between said outer faces of the wings and the flanges in the adjoining areas thereof, whereby said facing sheets lie smoothly across the joint between said wings and flanges.

3. In a slab door: a frame bar lhaving a longitudinal groove definedbetween spaced flanges having substantially parallel opposed inner walls; a joining bar having, at its end, tenon tongue meanssprojecting into saidl groove, and a pair of resilient abutmentwings on respective sides of said'tongue means, in opposed, embracing relation to the root areas of the outer walls of said tongue means, said wings at 'their tips having abutment shoulders set back from a tip area of said tongue means; said joining bar having lateral slots between said tongue means and the 'mner faces'of said wings whereby said inner faces are spaced outwardly from the outer faces of said tongue means for inward yielding movement of said wings relative to said tongue means; said'outer walls of said tongue means exerting outward pressure against said inner walls of the grooves whereby said tongue means is fri'ctionally Vgripped by said flanges; and facing sheets attached to the outer faces of said bar and bridging across the joints between saidabutment wings and said anges; said abutment shoulders and marginal flange faces being Vin closed-joint contact with one another in a plane substantially at rightangles to said tongue means and saidwings, and being freely shiftable in said plane relative to one another so as` to accommodate inward yielding of said wings to achieve flush relation between said outer faces of thewings and the flanges in the adjoining areas thereof, whereby said facing sheets lie smoothly across the joints between said wings and flanges.

References 'Cited inthe tile of this patent UNITED STATES PATENTS V552,578 Hill Jan. 7, 1896 2,152,694 Y Hoover Apr. 4, 1939 2,229,279 Cranston et al Jan. 21, 1941 2,622,999 Faussner Dec. v23, 1952 2,668,788 Waldherr '-Feb. 9, 1954 FOREIGNV PATENTS 770,526 France Sept. 15, 1934 489,518 Canada Jan. 13, 1953 

